Immutable infrastructure has skyrocketed in popularity during the past several years, especially in cloud-native applications. How software is produced, maintained, and deployed is drastically altering due to immutable infrastructure, which also accelerates development releases. Let’s discuss the definitions of mutable and immutable before moving on to a technical explanation.

Mutable: Anything that can be altered is mutable. It means you can still modify it after it has been deployed.

Immutable: Anything that can’t be altered. You cannot make any changes to it once it is fully created.

For instance, you might paint a door differently and alter the knobs to give it a new appearance. It can be changed such that. A washbasin is an immutable object at the same time. Replacing the washbasin if you wish to change its color is necessary. The same holds for a floor tile.

The terms mutability and immutability are used in software engineering and DevOps in the IT industry. The notion is used in object-oriented programming, software engineering, and infrastructure automation in DevOps. Immutable infrastructure is the main topic of this guide from a DevOps perspective.

What Does Immutable Infrastructure Mean?

Immutable infrastructure has gained momentum in part due to the development of cloud services. Servers (virtual machines) that never change after deployment are called immutable infrastructures. Servers operate differently under an immutable infrastructure paradigm. We do not want to maintain the current servers. Instead, we guarantee that a deployed server won't be altered in any way.

When it comes time to upgrade your server, you'll swap it out for a new one. For any corrections, improvements, or updates, the following steps should be taken:

• Create a new server from a shared image, add the necessary updates, packages, and services;
• Provision the new server to replace the old one;
• Validate the server;
• Decommission the old server.

Each redeployment (update) is precise, versioned, timestamped, and uses the same environment. If you need to roll back your environment, the prior servers are still accessible. Because of OS-level virtualization, this modification eliminates the need to debug malfunctioning instances, and the new servers can be deployed quickly.

Therefore, immutable infrastructure can hasten deployment, but is performance improved? In general, yes. Although uncommon, performance on a single instance occasionally needs to catch up to a changeable server's. Significantly simpler horizontal scaling enables quicker environment creation with more machines and faster deployments.

Optimum Practices for Immutable Infrastructure

Immutable infrastructure can be used effectively with the following tools and procedures to maximize its benefits:

• Complete automation of deployment (enhances predictability).
• Quick provisioning in cloud computing settings.
• Creating go-to methods for dealing with transient or stateful data.

Frequently Used Infrastructure Tools

The following is a list of some popular tools and services used to create immutable infrastructure:

• AWS, GCP
• Docker
• Kubernetes
• Spinnaker

Immutable infrastructure is the way of the future. These profound modifications touch every stage of the software development lifecycle, from devs to ops to end users. You should use them to boost your performance if you still need to start using them.

How to Implement Immutable Infrastructure?

When it comes to implementation, immutable infrastructure has specific needs. Executing it without automation, software design, or tooling concepts is feasible by merely adhering to the essential immutability principles. The following elements are usually advised for practicality:

• Servers in the ecosystem of cloud computing
  Other virtualized environments, such as containers, might be used, although some of the following criteria would change. The major purpose here is to have separate instances with quick provisioning from custom images and automated administration for creation and deletion via an API or equivalent.
• Complete pipeline automation for deployments
  It includes picture validation after its creation. Setting up this automation increases the initial expense of putting the infrastructure in place. However, it is a one-time expenditure that will be swiftly recovered.
• Service-oriented architecture
  It divides your infrastructure into conceptually independent, modular, and network-communicating parts. This component enables you to fully utilize service-oriented characteristics of cloud computing, such as IaaS and PaaS.
• Volatile, stateless application layer
  Your immutable servers are part of the stateless, volatile application layer. Everything in this place is volatile, meaning it can be swiftly and quickly rebuilt at any point without any data loss.
• The layer of persistent data
  It consists of two components.
  • Centralized logging contains extra information on the deployment of a server, such as an image identification via a version or a Git commit SHA. Storage of measurements and logs outside enables troubleshooting even when shell access is banned, or the server has been destroyed since servers are disposable in immutable infrastructure.
  • Block storage and cloud databases are external data stores for databases and other stateful data. Local storage is useless if your server is unstable. The information would have to be kept somewhere else.

Containers and immutable infrastructure can offer the elastic, adaptable infrastructures required for DevOps work schedules. This idea may be put into practice in a variety of ways. How much of your infrastructure you want to build on your own and how much you want to rely on paid services are all factors that influence your decision.

What are the Advantages of Immutable Infrastructure?

For medium-sized to enterprise-level businesses, immutable infrastructure offers several strategic benefits. Let's discuss them one by one.

• Cuts down on support calls
  Immutable infrastructure users experience much fewer support calls than non-users. When problems occur, they find it simpler to eliminate the instances causing them. The technical team can also swiftly identify the source of that failure and update the system to cure it.
• Increases the resolution of security incidents
  The blurred distinction between a typical operation and an exception presents one of the major obstacles when responding to security events. The difference between the two states is quite evident in an immutable infrastructure.
  Consequently, it is simpler to find exceptions, and machine learning can replace manual rules. Because versioning happens at the container level, that baseline is a trustworthy indicator of normalcy. Certain exceptions can be avoided before they happen.
• Remove configuration drift
  Supporting the servers becomes a time-consuming chore if you wonder if they all have the same setup. It typically occurs when several instances of the server definition are operating simultaneously. All it takes to create havoc is for someone to update a server configuration manually. 
  Thanks to an immutable architecture, only one instance of a server configuration running exists. And before its deployment, that instance underwent a comprehensive inspection.
• Eradicates synchronization duties
  While running, instances can be updated, leading to configuration drift and security issues. Continuous synchronization is a common solution to such a problem.
  It updates configuration modifications made since the last update by running scripts regularly. Regrettably, this method occasionally results in momentarily misconfigured systems. The technique may remove malware, but from a security perspective, it is not a wise security measure.

Summarizing the Adoption Path

There are many standard techniques or toolkits for adopting immutable infrastructure. IT orchestration, automation, and resource management are examples of related technologies still being developed. An enterprise with immutable infrastructure must have well-developed business processes and support network, server, and storage resources from the beginning.

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